Pressure controlled switch



Feb. 8, 1944. B. A. REYNOLDS PRESSURE CONTROLLED SWITCH Filed Dec. 23, 1942 ra/14 IIIlIIIIlIIlllIIIIIl/IIIIIIIII/III) viz/1' "II/111111141111 (111111111114 "0 'llIlIlI/IIIII wnnua/0air/11111111011100 INVENTOR .Burl H. Reynolds ATTORNEYS Patented Feb. 8, 1944 PRESSURE CONTROLLED SWITCH Burl A. Reynolds, 1.0m, Calif.

Application December 23, 1942, Serial No. 469,883

6 Claims.

This invention relates in general to an improved electric switch. a

The invention is directed in particular to, and it is one of the objects to provide, a switch which includes, in combination, a unique snap action con'tactor unit, and novel means to actuate said snap action contactor unit to effect make and break of the circuit in which the switch is interposed.

The switch, while being adaptable for many uses, is especially suited for use as a circuit control switch of refrigerating apparatus, and wherein the switch is actuated by force of a power mechanism responsive to the pressure in the fluid system of the refrigerator.

In connection with such use, a major object of the invention is to provide a switch in which the contactor unit actuating means includes a novel structural arrangement which is designed to provide easy and quick manual adjustment whereby the extent of the operating force required to actuate the contactor unit to switch closing position and to switch opening position may be independently and selectively varied. In other words, variation in the low and high pressure limits of the fluid in the refrigeration system, and between which the switch-controlled apparatus operates, may be independently obtained.

It is an additional object of the invention to provide a switch which includes a pair of annular, facing but axially spaced stop members, a shaft extending axially through said members in relatively slidable relation lengthwise, and a circular snap-action contactor unit disposed on the shaft between said members; said snapaction contactor unit comprising a multiplicity of segmental contact elements swingably radiating from a centering and retaining collar and secured in place thereon by a tensioned endless helical spring which frictionally engages in a circumferential groove in the circular assembly of said contact elements, the retaining collar being mounted on and movable by said shaft to effect snap action of said circular contact-or unit in one direction or the other whereby said contactor unit engages one or the other of said stop members, on one or both of which stop members contact plates are secured.

It is also an object of the invention to provide a switch, as in the preceding paragraph, in which the stop members are outwardly projecting radial flanges formed on axially alined but spaced cuplike housings surrounding the shaft and opening toward each other, said housings being mounted for independent and selective axial ad;

justment; the switch including a collar fixed on the shaft within each housing, and a spring between each collar and the adjacent end of the contactor unit centering and retaining collar.

A still further object of the invention is to provide a switch which is fast action and which accomplishes a sharp arcless and wiping make and break between the included snap action contactor unit and the contact plates relative to which said unit makes or breaks.

A further object of the invention is to provide a simple and inexpensive device and yet one which will be exceedingly efiective for the purpose for which it is designed.

These objects I accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawing similar characters of reference indicate corresponding parts in the several views:

Figure 1 is a plan view of the switch as mounted in a case, the top of the case bein removed.

Figure 2 is a longitudinal sectional elevation of the switch.

Figure 3 is a cross section on line 33 of Fig. 2.

Figure 4 is a cross section on line 4-4 of Fig. 2.

Referring now more particularly to the characters of reference on the drawing, the switch comprises a base I which is formed with a pair of spaced legs 2 which project therefrom in parallel relation.

Tubular sleeves or spindles 3 extend in axially alined relation through the legs 2 and are secured in connection therewith in rotatable but axially immovable relation. At their outer ends the spindles 3 terminate beyond the legs and pressure-calibrated adjustment wheels 4 and 4a are fixed on said end portions; said wheels including radially projecting pins 5. Finger 6 are supported by the legs 2 and closely overhang the periphery of wheels 4, and against which fingers the pins 5 engage upon predetermined rotative movement of the wheels and so as to limit the extent of rotation of the latter to substantially one full revolution.

Axially alined but spaced, cup-like housings 1 are threaded onto the inner and enlarged ends of spindles I, as at 8; said housings being open at adjacent ends. Guide pins 9 are secured on each housing parallel to but radially spaced from the axis thereof, and said guide pins slidably described assembly, such shaft beingjoumaled. 1

in the spindles 3 and projecting therebeyond at both ends in slidable relation thereto.

A circular, snap-action contactor unit, as

shown in the drawings and as hereinafter described in detail, is supported by shaft II and extends between annular flanges I2 formed on and projecting radially outwardly from adjacent ends of housings I. Such snap-action contactor unit comprises a multiplicity of segmental contact elements I3 arranged in circular assembly, said elements being wedge-shaped in a plane axially of the unit. At their inner ends the elements I3 engage or seat in a continuous V-groove formed in a centering and retaining collar I4 which is carried by a dielectric hub I5 slidably mounted on shaft II. the segmental contact elements I3 is secured together by an endless helical spring I6 which frictionally engages in a peripheral groove II formed in said circular assembly. Flanges I2 limit snapaction movement of the contactor unit in corresponding directions.

A pair of stop collars l8 and I8 respectively are flxed on the shaft II in spaced relation and each within one of the housings I; the distance between said collars being less than the distance between the inner surface of the ends of housings I whereby to permit of limited to-and-fro sliding movement of the shaft II. Compression springs 20 and 2I surround the shaft II between collar I8 and hub I5, and collar I9 and hub I5 respectively; said springs causing the hub to move with shaft I I.

One of the flanges I2 is faced with a pair of half-circle contact plates 22 mounted on said flange in insulated relation to each other and to said flange. Terminals or poles 23 extend through said flange I2 ininsulated relation and each connects with one of the contact plates 22. Wires 24 lead from poles 23 to binding posts 25 supported by a connector block 26 mounted within the case 21 which surrounds the entire switch.

To actuate the switch the shaft II is moved in one direction or the other axially, movement toward wheel 4a resulting in corresponding movement of the centering and retaining collar I4 and resultant snap-action movement of the contactor unit into engagement with the contact plates 22, as clearly shown in Fig. 2. This is the switch closing operation.

The switch opening operation is accomplished by moving shaft II axially towards adjustment wheel 4, such movement causing the contactor unit to have snap action toward the flange I2 opposite contact plates 22, and which is the open position of the switch.

Snap action of the contactor unit takes place by reason of the fact that with axial movement of the collar I4, the lower end portions of contact elements I3 are shifted until said elements pass dead center, whereupon the spring I8, which is thus placed under increased tension, causes such snap action of the unit to occur.

Selective regulation of the axial force which must be applied to shaft II to effect opening or closing of the switch is accomplished by adjustment of hand wheels 4 and 4a respectively; the periphery of said wheels having indicia inscribed thereon indicating such forces. Rotatlve adjust- The circular assembly of ment of wheels 4 and 4a varies the required switcn opening and closing force by reason of the fact that such rotative adjustment of said wheels causes the corresponding housings I to be ad vanced or retracted axially relative to the radial plane'in which the contactor unit passes dead center. Thus when the flanges I2 are a. greater distance from said plane, the force required on shaft II to accomplish snap action of the contactor unit is greater than the force required when said flanges are closer to said plane.

As previously indicated, the above described switch is capable of many uses, but is particularly designed for use to control the electric circuit of a refrigerator which includes a fluid pressure system to which the switch must be responsive. When so used a pressure responsive power mechanism of conventional type, as shown at 28, is mounted in connection with one end of the case 21; the actuating stem 29 of said power mechanism projecting into the case and being connected with the adjacent end of shaft I I. The mechanism 28 is connected to the fluid pressure system of the refrigerator by a conduit 30, and as said mechanism 28 responds in one direction or the other to the pressure in said system, the shaft II is correspondingly moved, resulting in opening and closing of the switch at the proper times, or when the pressures in the refrigerating system correspond to the indicia on wheels 4 and 4a.

At the end opposite power mechanism 28 the case 21 is provided with a push button M which, when pushed inwardly, move the shaft II in a direction to cause opening of the switch. The push button effect is a safety device and is adapted to be actuated by the high pressure bellows with which some switches for this service are equipped, and which functions in the event of excessive head pressure being in the system. Since the contact elements I3, when engaged with plates 22, move radially out before the action of spring I6 swings said elements away from the plates, a wiping action between the plates and elements is had which maintains the contacting surfaces clean and assures proper electrical connection.

The collars I8 and I9 prevent possible damage to the switch in the event of excessive pressure on shaft I I by coming in contact with the hubs of housings 'I at the ends of the throw of the contactor unit. The counteracting springs 20 and 2| act on the floating hub I 5 to prevent the contact elements from possibly remaining on dead center, and which would cause arcing at the contact points at the time of breaking the contact or opening the switch.

From the foregoing description it will be readily seen that I have produced such a. device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described my invention What I claim as new and useful and desire to secure by Letters Patent is:

1. A switch comprising a circular contactor unit arranged for snap-action in opposite directions, means operative to effect snap action of said contactor unit in either direction, and a pair of spaced stop elements between which said contactor unit projects, one element limiting snap action of the unit in one direction, and the other element limiting snap action of the unit in the other direction, the circuit being closed by the contactor unit when in engagement with one of said elements; said contactor unit comprising a multiplicity of adjacent contact elements in the form of a segment of a circle and symmetrically arranged in circular assembly, centering and retaining means supporting said contact elements at their inner end for swinging movement, the contact elements being Wedge shaped in a plane axially of the contact unit; and a tensioned endless spring surrounding the circular assembly of said contact elements and frictionally engaging in a peripheral groove formed in the large end of said contact elements.

2. A switch comprising a base, a pair of legs projecting from the base in parallel relation, tubular spindles extending through said legs in rotatable but axially immovable relation, adjustment wheels fixed on the outer ends of said spindles beyond the legs, cup-like housings threaded on the inner ends of said spindles inwardly of the legs, means holding said housings against rotation without limiting axial movement thereof, said cup-like housings opening toward each other and terminating at adjacent ends in spaced relation and at said adjacent ends being formed with annular flanges, a shaft ex-. tending between said spindles and projecting in slidable relation therethrough, and a circular snap-action contactor unit surrounding the shaft and projecting between said flanges, said contactor unit including a hub mounted on the shaft and movable therewith; movement of the shaft and hub in one direction or the other being operative to effect snap action of the contactor unit toward one flange or the other, said flanges providing stops limiting said snap action of the contactor unit, the switch being closed upon snap action of the contactor unit in one direction.

3. A switch comprising a pair of annular stop elements disposed in axially alined spaced-apart relation, a shaft extending axially and relatively slidably through said stop elements, means mounting said stop elements for selective and independent adjustment axially relative to each other and to the shaft, and a circular contactor unit adapted for snap action in opposite directions, said contactor unit being disposed concentrically between said stop elements and including a hub on and movable with the shaft, one stop element limiting snap action of the contactor unit in one direction and the other stop element limiting snap action of the contactor unit in the other direction, the circuit through the switch being closed when said contactor unit is in engagement with one of said stop elements.

4. A switch comprising a pair of cup-like housings disposed in axially alined spaced-apart relation, said housings facing each other and being formed at adjacent ends with annular stop elements, a shaft extending axially and relatively slidably through said housings, means mounting said housings for selective and independent adjustment axially relative to each other and to the shaft, and a circular contactor unit adapted for snap action in opposite directions, said contactor unit being disposed concentrically between said stop elements and including a hub on and movable with the shaft, one stop element limiting snap action of the contactor unit in one direction and the other stop element limiting snap action of the contactor unit in the other direction, the circuit through the switch being closed when said contactor unit is in engagement with one of said stop elements.

5. A switch comprising a pair of cup-like housings disposed in axially alined spaced-apart relation', said housings facing each other and being formed at adjacent ends with annular stop elements, a shaft extending axially and relatively slidably through said housings, means mounting said housings for selective and independent adjustment axially relative to each other and to the shaft, and a circular contactor unit adapted for snap action in opposite directions, said contactor unit being disposed concentrically between said stop elements and including a hub on and movable with the shaft, one stop element limiting snap action of the contactor unit in one direction and the other stop element limiting snap action of the contactor unit in the other direction, the circuit through the switch being closed when said contactor unit is in engagement with one of said stop elements; said means comprising spindles rotatably surrounding the shaft but held against axial movement, the inner end of said spindles being threaded into the housings and the outer ends of said spindles being fitted with adjustment wheels, andmeans arranged to hold said housings against rotation without limiting axial movement thereof,

6. A switch comprising a pair of cup-like housings disposed in axially alined spaced-apart relation, said housings facing each other and being formed at adjacent ends with annular stop elements, a shaft extending axially and relatively slidably through said housings, means mounting said housings for selective and independent adjustment axially relative to each other and to the shaft, and a circular contactor unit adapted for snap action in opposite directions, said contactor unit being disposed concentrically between said stop elements and including a hub slidable on the shaft, one stop element limiting snap action of the contactor unit in one direction and the other stop element limiting snap action of the contactor unit in the other direction, the circuit through the switch being closed when said contactor unit is in engagement with one of said stop elements; there being stop collar fixed on the shaft on opposite sides of the hub and within corresponding housings, and compression springs surrounding the shaft and engaged between said stop collars and adjacent ends of the hub.

BURL A. REYNOLDS. 

